Run torch backend pipeline

python/torch_mlir/fx.py

@@ -23,13 +23,27 @@
 )
 
 
-def _simplify_lowering(verbose, output_type, torch_mod):
+def _simplify_lowering(verbose, output_type, torch_mod, backend_legal_ops=None,
+                       extra_library_file_name=None):
+    # TODO: pass backend_legal_ops/extra_library_file_name by caller
+    if backend_legal_ops is None:
+        backend_legal_ops = []
+    if extra_library_file_name is None:
+        extra_library_file_name = ""
+    option_string = ("{backend-legal-ops=" + ",".join(backend_legal_ops) +
+                     " extra-library=" + extra_library_file_name + "}")
     run_pipeline_with_repro_report(
         torch_mod,
         f"builtin.module(torch-simplification-pipeline)",
         "Simplification pipeline for torch dialect",
         enable_ir_printing=verbose,
     )
+    run_pipeline_with_repro_report(
+        torch_mod,
+        f"builtin.module(torch-function-to-torch-backend-pipeline{option_string})",
+        "Lowering TorchFX IR -> Torch Backend IR",
+        enable_ir_printing=verbose,
+    )
     return lower_mlir_module(verbose, output_type, torch_mod)